Grenaa Varmeværk expects to have a fully operational waste heat facility in place by summer 2027, using heat from its neighbouring company, De Danske Gærfabrikker. At the same time, the yeast factory will become a district heating customer.
Danish text by Kim Vejrup, the Danish District Heating Association
The idea of utilising waste heat from the nearby yeast factory has been under development at Grenaa Varmeværk (District Heating) for a long time. However, the former price cap on waste heat made it difficult to turn the project from an idea into reality.
When the price cap was finally removed in summer 2025, Søren Gertsen, CEO of Grenaa Varmeværk, resumed work on making the project happen. The waste heat facility is now expected to be commissioned around summer 2027.
“The project has been approved both by our own board and by De Danske Gærfabrikker, so everything is on track,” says Søren Gertsen.
Norddjurs Municipality has also approved the new building that will house the heat pump facility. The building will cover just under 350 square metres and will be located on Grenaa Varmeværk’s site.
Construction work to begin this summer
According to Søren Gertsen, the supply pipes from the yeast factory will be very short, meaning heat loss will be almost negligible.
“The current plan is to begin groundworks this summer, including the installation of the large cooling pipes. It is too early to start now, as the ground needs to be dry before we can begin,” he explains.
Once the facility is operational, Grenaa Varmeværk will receive water from the yeast factory at 32°C. The energy will then be extracted before the water is returned across the property boundary at 17°C.
“This is where the synergy arises, because the yeast factory can then use the return water to cool its large tanks,” says Søren Gertsen.
The building for the heat pump facility is expected to be ready in December, while the heat pump itself is scheduled for installation in January 2027.
Waste heat for 1,600 homes per year
Grenaa Varmeværk is now moving closer to using waste heat in its district heating network, which currently serves around 5,600 customers. Søren Gertsen acknowledges that it has been a long process, even after the price cap was finally removed in summer 2025.
“The planning has taken an incredibly long time. On top of that, it also takes time to have the necessary equipment delivered. Coordinating all of this has been a major task,” he says.
The benefits, however, are significant. According to Søren Gertsen, the cooperation will help deliver cheaper heat to Grenaa Varmeværk’s 5,600 consumers, partly because the waste heat will be able to supply the full annual heating demand of 1,600 standard homes.
In addition, the district heating supply will become more sustainable and future-proof.
Supplying hot water to the yeast factory
As an added benefit, the close cooperation with the neighbouring yeast factory has also led to De Danske Gærfabrikker becoming a district heating customer. The factory will receive hot water from Grenaa Varmeværk, enabling it to phase out the coal boiler currently used for process heat.
Søren Gertsen explains that the future heat pump facility will have a capacity of 6 MW, which is considerably larger than originally expected. Through the cooperation, the yeast factory will now be connected to the district heating utility.
“We will definitely feel the impact. Connecting the yeast factory is equivalent to connecting 2,000 homes at once. With the roughly 5,600 customers we have today, this corresponds to a capacity expansion of around 15–20%,” says Søren Gertsen.
He sees the project as having major potential for Grenaa Varmeværk as well. The utility will supply the factory with water at between 90°C and 93°C for use in its production process.
The English version of this article was produced with AI assistance and reviewed by DBDH.
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